Replacement guide for poppet valve stems



Aug. 1l, 1953 c. c. CARTER REPLACEMENT GUIDE FOR POPPET VALVE STEMSFiled May 7, 1952 nventor Ehara'i E.- [lamer F I G 6.

IHIIIIIU I @Zag-@ Gttornegs Patented Aug. 11, 1953 REPLACEMENT GUIDE FORPOPPET VALVE STEMS Charles C. Carter, Lubbock, Tex.

Application May 7, 1952, Serial No. 286,533

(Cl. 12S- 188) 3 Claims.

This invention relates to poppet valve assemblies, such as are providedin internal combustion engines for control of the intake and exhaustgases, and such fluids as oil which are entrained therein. Y

New and used engines of this type, primarily designed for use in motorvehicles, are extensively used as stationary engines to operate pumps insections of the country requiring irrigation. They are also frequentlyused for other purposes and butane, propane and natural gas, instead ofgasoline, have been found to have certain advantages as fuels foroperating such engines. Among these advantages, are low cost of the fuelin many localities and the ability to store a supply of such fuels aspropane and vbutane, drawing upon the supply for a long period of time,in a lcomparatively small space.

A comparatively inexpensive engine, suitable for stationary use, in theFord automobile engine of the type in which the cylinder block isprovided with circular poppet valve seats and companion axially alignedvalve stem guide bores, of rather large diameter, each companion seatand bore for cooperation with a poppet valve system or assemblyincluding the poppet valve, a valve stem guide, somewhat looselydisposed in the bore, spring retainer on the valve stem and expansioncoil spring, normally compressed between the spring retainer and guide,all of which may be slidably removed, while in assembled condition,through the valve seat opening and bore, after a forked or bifurcatedvalve guide retainer or keeper has been detached from the guide.Examples of some of the types of such poppet valve assemblies are shownin patents to Douglas et al., 2,112,832, April 5, 1938, and Gass,2,207,400, July 9, 1940. Repair parts for such poppet valve assembliesare readily available in most populated sections of the country. Theexpansion coil springs thereof are uniformally made to suchspecifications that in use they are each compressed to a veryappropriate degree for eiicienci7 in closing the valve when the throwside of the cam is not acting upon valve lifter, and to reduce wear to aminimum.

In practice, however, it has been found that engines equipped with suchtype of poppet valve assembly (although the free t valve stem guidesrender installation of new parts of those which have become worn, acomparatively easy job) do not remain in satisfactory operativecondition for any great length of time, when such dry gases(comparatively free of lubricant) as propane, butane, and natural gasare used as fuels. The

valve seats become out-of-round through use, and sometimes, to someextent, the valve head becomes worn and there is leakage of gas due toimperfect seating of the valve at the appropriate time in the cycle ofoperation of the piston in the combustion chamber controlled by thevalve. I attribute this to the lack of lubricant between the valveproper and its seat, combined with looseness of the valve guide. Wherelubricant is naturally entrained in fuels such as gasoline, thisout-of-round condition seldom occurs, even over a long period of time,and while it may 'be that the valve spring terminal portion engaging thevalve stem guide may have a tendency to cant, so to speak, thecomparatively loose guide to a position where the valve head or discengages first with line contact at its tapered portion, with the taperedportion of the valve seat, and then, due to the expansion of the seat,causes surface-to-surface contact between such tapered portions, thelubricant entrained in the wet fuel prevents wear at this linecontacting portion.

A major object of the invention is to provide a replacement valve stemguide which will obviate the wear mentioned when fuels such as butane,propane and natural gas mixtures are employed in internal combustionengines of the class described.

Another major object is to provide an eiicient force-ntted replacementvalve stem guide which has the advantages just mentioned.

An important object is to provide a new replacement valve stem guidewhich requires no complicated machining since it comprises an integralbody of three stepped cylindrical portions, provided with a Valve vstemaccommodating bore, and a simple spacing and retaining ring.

A further important object is to provide a replacement valve stem guidewhich will remain in its proper position, without the employment of aconventional valve guide retainer and the associated groove or recessesfor the retainer in the conventional valve guide.

Yet another important object is to provide a valve guide which iseconomical to manufacture and comprises but two parts.

Other objects and advantages of the invention will be apparent duringthe course of the following detailed description of the invention, takenin connection with the accompanying drawing, forming a part of thisdisclosure, and in which drawing:

Fig. 1 is a vertical section of an internal combustion engine blockcontaining a conventional poppet valve assembly.

Fig. 2 is an elevation of the valve spring of Figs. 1 and 4.

Fig. 3 is a perspective view of the tapered surface of a valve seat,which may be employed with the valve assembly of Figs. l and 4, butshowing wear to the surface.

Fig. 4 is a View, somewhat like that of Fig. 1 but showing my newreplacement Valve stem guide substituted for the guide of Fig. 1.

Fig. 5 is an elevation of the new guide body of Fig. l.

Fig. 6 is an elevation of a spacing and retaining ring of the newreplacement guide.

In the drawing, wherein for the purpose of illustration is shown apreferred embodiment or" the invention and wherein similar referencecharacters designate corresponding parts throughout the several views,the letter A designa-tes an internal combustion engine cylinder block;B, a poppet valve assembly or system associated therewith; and C the newreplacement guide.

The internal combustion engine cylinder block A is shown as of the typeprovided with a circular poppet valve seat it and an axially alignedvalve stem guide bore i i extending therefrom having diameterssufficiently large enough to permit the several parts of the pop-petvalve assembly or system B to be slidably removed therefrom, while inassembled condition, through the valve seat lll. At the lower end or"the valve stein guide bore li is a downwardly-facing shoulder Z2 formedin the block and normally adapted to receive portions of the biiurcatedend of a conventional valve guide retainer i3.

A valve assembly or system E is shown to include a valve stem l5, aloosely-fitting valve stem guide i6, a spring retainer il' on the steinand an expansion coil spring it normally compressed between the springretainer il and guide le. The guide l@ is peripherally grooved as at itto receive the other parts of the biiurcated end the retainer i3, as iswell Known in the art.

When using so-called non-lubricating fuels, such as butane, propane,natural gas mixtures and the like, the tapered or bevelled surface Hl ofthe valve seat often very quickly becomes unevenly worn or out-of-roundas at i5 in Fig. 3, or the under tapered side 2d of the valve head ordisc 2l becomes unevenly worn, as stated.

The new replacement guide C, shown in Fig. 4, includes a cylindricalbody 25 comprising three stepped portions 25, 2l' and dii, and the lrstor uppermost cylindrical body portion 28 is adapted to extend throughthe bore l l substantially as in Fig. 3 in a force fit with the wallsthereof. The second or intermediate portion 2l provides a dependingsleeve portion and is of lesser diameter than the portion 2G so that adownwardly-facing shoulder ES is provided, and the third or lowermostend portion 23 is of less diameter than the portion 2l'. When properlypositioned, as in Fig. 4, the shoulders l2 and 29 are in substantiallythe same horizontal plane. The external diameter of the sleeve portion2l is such that there is a close t of the upper end portion 22 of thespring I3, which upper end portion encircles a part of this portion 2l'.Extending through the body 25 from its upper face 3i) to its lower face3l is a bore 32 to slidably receive the valve stem I5.

Encircling the upper part of the sleeve portion 2l and with one flatface 35 abutting the shoulders l2 and 29 is a spacing and retainingelement or ring 36. Preferably, the element 36 has a sliding fit at itsinner periphery 38 with the portion 2l but its outer peripherypreferably does not extend to the adjacent wall of the bore Il although,of course, the diameter of this periphery is greater than that of thebody portion 26. The other or lower flat face 3l of the element 36 isadapted to contact the terminal coil of the end portion 22 oi the springi8 so that the element 35 is forced up against the shoulders i2 and 29,and the thickness of the element 36 is such that the element 36 willretain the valve spring I8 in normal compressed and centered conditionbetween the element 36 and the spring retainer I1.-

Upon removal of the poppet valve assembly B of Fig. l in the well-knownway, the guide i6 is discarded and the worn valve seat it is replaced bya new one. The bore li may be reamed, if necessary, and the new guidebody 25 be either driven or pressed into this bore; the spacing andretaining element 36 inserted to abut the shoulders l2 and 29 andtherest of the valve assembly inserted in any desired sequence to completethe installation.

Various changes may be made to the form of the invention shown anddescribed without departing from the spirit of the invention or scope ofthe claims.

What is claimed is:

l. For use in an internal combustion engine cylind r block of the typeprovided with a circular poppet valve seat and axially aligned valvestem guide bore having diameters sufficiently to permit those parts ofthe poppet valve system comprising the valve stem, a loosely fittingvalve stein guide, spring retainer on the stem and expansion coil springnormally compressed between the spring retainer and guide, to beslidably removed, while in assembled condition, through said valve seatand valve stem guide bore; the improvement 'which comprises areplacement guide through which the valve stem extends, comprising acylindrical body portion having a force rit in said bore, with its lowerend substantially iush with the bottom end of said bore, and a dependingsleeve portion of reduced diameter extending from. the lower end oi saidbody portion. and surrounding the valve stem, whereby a cwnwardly racingshoulder is presented at the bottom of the 1cody portion and surroundingsaid sleeve, and a combination spacing and retaining ring against whichthe valve spring abuts, said ring slidable engagement with andsurrounding said sleeve portion and engaging said shoulder, said ring ofan external diameter greater than the diameter of said body portion andengaging the surface of the block beneath said bore, and said ring of athickness to retain the valve spring in normal compressed conditionbetween the ring and spring retainer.

2. The improvement as set forth in claim l in which said sleeve portionnext below said ring is of an external diameter substantially equal tothe internal diameter of the coil spring, for engagement and centeringcooperation therewith.

3. For use in an internal combustion engine cylinder block of the typeprovided with a circular poppet Valve seat and axially aligned valvestem guide bore having diameters sumciently large 13g permit those partsoi' the poppet valve system comprising the valve stem, a loosely fittingvalve stem guide, spring retainer on the stem and expension coil springnormally compressed between the spring retainer and guide, to beslidably removed, while in assembled condition, through said valve seatand valve stem guide bore; the improvement which comprises a replacementguide through which the valve stem extends, comprising a cylindricalbody portion having a force t in said bore, with its lower endsubstantially flush with the bottom end of said bore, and a dependingsleeve portion of reduced diameter extending from the lower end of saidbody portion and surrounding the valve stem, whereby a downwardly facingshoulder is presented at the bottom of the body portion and surroundingsaid sleeve, and a combinati-on spacing and retaining 10 element againstwhich the upper end portion of the valve spring abuts, said spacing andretaining element engaging said shoulder and the surface of the blockbeneath said bore, and said spacing and retaining element :of athickness tc retain the valve spring in normal compressed conditionbetween it and the spring retainer.

CHARLES C. CARTER.

No references cited.

